Here is a video of “Purple Rain”–watch all the way through to see how Clapton jams out the “oooooh” part:

Eric Clapton, Royal Albert Hall, London, UK, May 13, 2019, Setlist

Que Sera Sera
Motherless Children
Key to the Highway
Pretending
I’m Your Hootchie Coochie Man
I Shot the Sheriff
Driftin’ Blues
Nobody Knows You When You’re Down and Out
Tears in Heaven
Change the World
Running on Faith
Tearing Us Apart
Holy Mother
Crossroads
Five Long Years
Layla